RFID elements include tags and labels and have many uses including inventory control. Many different manufacturers have been attempting to find a solution for tagging metal and liquid containing objects utilizing ultra high frequency UHF RFID inlays. These inlays can typically be read at greater distances (many meters) than can the older, high frequency (HF) RFID inlays but, as a result, can interact with metals or certain other materials if in close proximity.
Traditionally RFID on metal tags have been embedded inside of durable plastics through an injection molding process, using a technique called “in-mold embedded”. This requires the manufacturer to open the mold die up and to place the RFID inlay inside of the injection mold die prior to injecting the molten plastics around the inlay. Because the inlay becomes exposed to relatively high temperatures from molten plastics, a significant portion of the inlays are destroyed because of the excessive heat. It is also a very labor intensive process that requires handling of these tags individually one at a time. Typical in-mold RFID on metal tags are made of ABS polycarbonates and usually surround the RFID inlay with a significant amount of material to give it a robust durable characteristic.
Others have incorporated ferro-magnetic materials and all sorts of magnetic coatings to enhance the read range of an RFID inlay when attached to metal. To a certain extent these approaches become successful but they are relatively expensive materials to work with.